As climate change warms the planet, high ambient temperatures are expected to become more common and intense globally. Researchers from the Yale School of Public Health (YSPH) have investigated the impact of rising temperatures on human health, finding that exposure to high ambient temperatures during pregnancy can adversely affect offspring health.
High temperatures exposure during pregnancy increases childhood cancer risk
This study published in The Lancet Planetary Health is the first to evaluate the association between hot temperatures during pregnancy and the risk of childhood cancer, specifically acute lymphoblastic leukemia (ALL). Tormod Rogne, the study’s first author, emphasizes that high ambient temperature may not only have immediate health effects but also contribute to future chronic diseases.
ALL, the most common type of childhood cancer, has seen an increasing incidence in recent decades, disproportionately affecting Latino children in the US. Past studies have shown that most childhood ALL cases have prenatal origins, with environmental exposures like air pollution being linked to increased risk. The first trimester is considered the most critical period for developmental changes in blood cell production, according to Xiaomei Ma, senior author of the study.
Segregated communities likely to feel effects of heat exposure
Despite being a rare disease overall, leukemia is the most common cancer among children and adolescents, accounting for about one-third of all cancers in this group. Latino children have a 30-40% increased risk of ALL compared to non-Latino white children, with the disease being more common in boys. Racial and ethnic minority groups are more vulnerable to heat exposure due to factors like occupational and residential segregation.
The research team used California birth records and the California Cancer Registry to identify ALL cases diagnosed in children 14 years and younger, focusing on warm months from May to September. A mean weekly temperature of 30°C (86°F) was associated with nearly double the risk of ALL compared to 10°C (50°F).
The potential mechanisms linking heat exposure in pregnancy to ALL remain unclear, but may involve epigenetic changes, inflammation, or oxidative stress.
